Motion
In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...
, the process of movement, is described using specific
anatomical terms. Motion includes movement of
organs
In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
,
joint
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw ...
s,
limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative to the
anatomical position
The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with r ...
of the body parts involved.
Anatomists and others use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing unique movements such as those of the hands, feet, and eyes.
In general, motion is classified according to the
anatomical plane
An anatomical plane is a hypothetical plane used to transect the body, in order to describe the location of structures or the direction of movements. In human and animal anatomy, three principal planes are used:
* The sagittal plane or latera ...
it occurs in. ''Flexion'' and ''extension'' are examples of ''angular'' motions, in which two axes of a joint are brought closer together or moved further apart. ''Rotational'' motion may occur at other joints, for example the
shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
, and are described as ''internal'' or ''external''. Other terms, such as ''elevation'' and ''depression'', describe movement above or below the horizontal plane. Many anatomical terms derive from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
terms with the same meaning.
Classification
Motions are classified after the
anatomical plane
An anatomical plane is a hypothetical plane used to transect the body, in order to describe the location of structures or the direction of movements. In human and animal anatomy, three principal planes are used:
* The sagittal plane or latera ...
s they occur in, although movement is more often than not a combination of different motions occurring simultaneously in several planes. Motions can be split into categories relating to the nature of the joints involved:
* ''Gliding'' motions occur between flat surfaces, such as in the
intervertebral disc
An intervertebral disc (or intervertebral fibrocartilage) lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the vertebrae, to act as a ligament to hold t ...
s or between the
carpal bones of the
wrist
In human anatomy, the wrist is variously defined as (1) the Carpal bones, carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known ...
, and the
metacarpal bones
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...
of the
hand
A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "h ...
.
* ''Angular'' motions occur over
synovial joint
A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulat ...
s and causes them to either increase or decrease angles between bones.
* ''Rotational'' motions move a structure in a
rotation
Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...
al motion along a longitudinal axis, such as turning the head to look to either side.
Apart from this motions can also be divided into:
* ''Linear'' motions (or ''translatory'' motions), which move in a line between two points. ''Rectilinear'' motion is motion in a straight line between two points, whereas ''curvilinear'' motion is motion following a curved path.
* ''Angular'' motions (or ''rotary'' motions) occur when an object is around another object increasing or decreasing the angle. The different parts of the object do not move the same distance. Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle.
The study of movement in the human body is known as
kinesiology
Kinesiology () is the scientific study of human body movement. Kinesiology addresses physiological, anatomical, biomechanical, pathological, neuropsychological principles and mechanisms of movement. Applications of kinesiology to human health ...
. A categoric list of movements and the
muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
s involved can be found at
list of movements of the human body
The list below describes such skeletal movements as normally are possible in particular joints of the human body. Other animals have different degrees of movement at their respective joints; this is because of differences in positions of musc ...
.
Abnormal motion
The prefix ''hyper-'' is sometimes added to describe movement beyond the normal limits, such as in ''
hypermobility'', ''hyperflexion'' or ''hyperextension''. The
range of motion
Range of motion (or ROM), is the linear or angular distance that a moving object may normally travel while properly attached to another. It is also called range of travel (or ROT), particularly when talking about mechanical devices and in mechanic ...
describes the total range of motion that a joint is able to do. For example, if a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion, then it can be described as ''hyperextended''. Hyperextension increases the stress on the
ligament
A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the:
* Peritoneal li ...
s of a joint, and is not always because of a voluntary movement. It may be a result of accidents, falls, or other causes of trauma. It may also be used in surgery, such as in temporarily dislocating joints for surgical procedures. Or it may be used as a
pain compliance
Pain compliance is the use of painful stimulus to control or direct an organism. The stimulus can be manual (brute force, placing pressure on painful areas, or use of painful hyperextension or hyperflexion on joints), use tools such as a whip or ...
method to force a person to take a certain action, such as allowing a police officer to take him into custody.
General motion
These are general terms that can be used to describe most movements the body makes. Most terms have a clear opposite, and so are treated in pairs.
Flexion and extension
Flexion and extension describe movements that affect the angle between two parts of the body. These terms come from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
words with the same meaning.), "to bend" ( la, flectere)
Flexion describes a bending movement that ''decreases'' the angle between a segment and its proximal segment. For example, bending the
elbow
The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the media ...
, or clenching a hand into a fist, are examples of flexion. When a person is sitting down, the knees are flexed. When a joint can move forward and backward, such as the neck and trunk, flexion is movement in the anterior direction. When the chin is against the chest, the neck is flexed, and the trunk is flexed when a person leans forward. Flexion of the shoulder or hip is movement of the arm or leg forward.
Extension is the opposite of flexion, describing a straightening movement that ''increases'' the angle between body parts. For example, when standing up, the knees are extended. When a joint can move forward and backward, such as the neck and trunk, extension is movement in the posterior direction. Extension of the hip or shoulder moves the arm or leg backward. Even for other upper extremity joints - elbow and wrist, movement behind results in extension. Except for knee, ankle, and wrist, where the distal end has to move in the anterior direction for it to be called extension.
With regard to the
toe
Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being ''plan ...
s, flexion means curling them downward whereas extension means uncurling them or raising them upward.
Abduction and adduction
Abduction is the motion of a structure away from the midline while adduction refers to motion towards the center of the body. The center of the body is defined as the
midsagittal
The median plane also called a mid-sagittal plane is used to describe the sagittal plane as it bisects the body vertically through the midline marked by the navel, dividing the body exactly in left and right side.
The term parasagittal plane is u ...
or
longitudinal
Longitudinal is a geometric term of location which may refer to:
* Longitude
** Line of longitude, also called a meridian
* Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicl ...
plane. These terms come from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
words with similar meanings, ''ab-'' being the Latin prefix indicating "away," ''ad-'' indicating "toward," and ''ducere'' meaning "to draw or pull".), "to lead away" la, abducere
Abduction is a motion that pulls a structure or part ''away from'' the midline of the body, carried out by one or more abductor muscles. In the case of fingers and toes, it is spreading the digits apart, away from the centerline of the hand or foot. For example, raising the arms up, such as when
tightrope
Tightrope walking, also called funambulism, is the skill of walking along a thin wire or rope. It has a long tradition in various countries and is commonly associated with the circus. Other skills similar to tightrope walking include slack rope ...
-walking, is an example of abduction at the
shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
. When the legs are splayed at the hip, such as when doing a
star jump or doing a
split
Split(s) or The Split may refer to:
Places
* Split, Croatia, the largest coastal city in Croatia
* Split Island, Canada, an island in the Hudson Bay
* Split Island, Falkland Islands
* Split Island, Fiji, better known as Hạfliua
Arts, enterta ...
, the legs are abducted at the hip.
Adduction is a motion that pulls a structure or part ''towards'' the midline of the body, or towards the midline of a limb, carried out by one or more adductor muscles. In the case of fingers and toes, it is bringing the digits together, towards the centerline of the hand or foot. Dropping the arms to the sides, and bringing the knees together, are examples of adduction.
Adduction of the
wrist
In human anatomy, the wrist is variously defined as (1) the Carpal bones, carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known ...
is also known as ulnar deviation which moves the hand towards the
ulnar styloid (or, towards the
little finger
The little finger, or pinkie, also known as the baby finger, fifth digit, or pinky finger, is the most ulnar and smallest digit of the human hand, and next to the ring finger.
Etymology
The word "pinkie" is derived from the Dutch word ''p ...
). Abduction of the wrist is also called radial deviation which moves the hand moving towards the
radial styloid (or, towards the
thumb
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...
).
[See]
for appropriate image
/ref>
Elevation and depression
The terms elevation and depression refer to movement above and below the horizontal. They derive from the Latin terms with similar meanings), "to raise" ( la, elevare)
Elevation is movement in a superior direction. For example, shrugging is an example of elevation of the scapula.
Depression is movement in an inferior direction, the opposite of elevation.
Rotation
Rotation of body parts is referred to as internal or external, referring to rotation towards or away from the center of the body.
Internal rotation (''medial rotation'' or ''intorsion'') is rotation towards the axis of the body, carried out by internal rotators.
External rotation (''lateral rotation'' or ''extorsion'') is rotation away from the center of the body, carried out by external rotators.
Internal and external rotators make up the rotator cuff
The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are the supraspi ...
, a group of muscles that help to stabilize the shoulder joint
The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...
.
File:Babaji.jpg, The lotus position of yoga
Yoga (; sa, योग, lit=yoke' or 'union ) is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India and aim to control (yoke) and still the mind, recognizing a detached witness-consciou ...
, demonstrating ''external rotation'' of the thigh at the hip.
File:Cable-internal-rotation-2.png, Rotating the arm away from the body is ''external rotation''.
File:Cable-internal-rotation-1.png, Rotating the arm closer to the body is ''internal rotation''.
Other
* '' Anterograde'' and '' retrograde'' flow refer to movement of blood or other fluids in a normal (anterograde) or abnormal (retrograde) direction.
* '' Circumduction'' is a conical movement of a body part, such as a ball and socket joint
The ball-and-socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number o ...
or the eye. Circumduction is a combination of flexion, extension, adduction and abduction. Circumduction can be best performed at ball and socket joints, such as the hip
In vertebrate anatomy, hip (or "coxa"Latin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) in medical terminology) refers to either an anatomical region or a joint.
The hip region is ...
and shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
, but may also be performed by other parts of the body such as fingers, hands, feet, and head. For example, circumduction occurs when spinning the arm when performing a serve in tennis
Tennis is a racket sport that is played either individually against a single opponent ( singles) or between two teams of two players each ( doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball ...
or bowling a cricket ball
A cricket ball is a hard, solid ball used to play cricket. A cricket ball consists of a cork core wound with string then a leather cover stitched on, and manufacture is regulated by cricket law at first-class level. The trajectory of a crick ...
.
* '' Reduction'' is a motion returning a bone to its original state, such as a shoulder reduction following shoulder dislocation
A dislocated shoulder is a condition in which the head of the humerus is detached from the shoulder joint. Symptoms include shoulder pain and instability. Complications may include a Bankart lesion, Hill-Sachs lesion, rotator cuff tear, or inj ...
, or reduction of a hernia
A hernia is the abnormal exit of tissue or an organ (anatomy), organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the gr ...
.
File:Heather Watson Serve.jpg, The swinging action made during a tennis serve
A serve (or, more formally, a service) in tennis is a shot to start a point. A player will hit the ball with a racquet so it will fall into the diagonally opposite service box without being stopped by the net. Normally players begin a serve by t ...
is an example of ''circumduction''
Special motion
Hands and feet
Flexion and extension of the foot
''Dorsiflexion'' and ''plantar flexion'' refer to extension or flexion of the foot at the ankle. These terms refer to flexion in direction of the "back" of the foot, which is the upper surface of the foot when standing, and flexion in direction of the sole of the foot. These terms are used to resolve confusion, as technically ''extension'' of the joint is dorsiflexion, which could be considered counter-intuitive as the motion reduces the angle between the foot and the leg.
Dorsiflexion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...
is where the toes are brought closer to the shin
Shin may refer to:
Biology
* The front part of the human leg below the knee
* Shinbone, the tibia, the larger of the two bones in the leg below the knee in vertebrates
Names
* Shin (given name) (Katakana: シン, Hiragana: しん), a Japanese ...
. This decreases the angle between the dorsum of the foot and the leg
A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element ca ...
. For example, when walking on the heel
The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus or heel bone, behind the articulation of the bones of the lower Human leg, leg.
Structure
To distribute the compressive for ...
s the ankle is described as being in dorsiflexion.
Plantar flexion or plantarflexion is the movement which decreases the angle between the sole of the foot and the back of the leg; for example, the movement when depressing a car pedal or standing on tiptoes.
File:017 'Ballerina' 18x24 oil on linen.jpg, A ballerina
A ballet dancer ( it, ballerina fem.; ''ballerino'' masc.) is a person who practices the art of classical ballet. Both females and males can practice ballet; however, dancers have a strict hierarchy and strict gender roles. They rely on yea ...
, demonstrating ''plantar flexion'' of the feet
File:Dorsiplantar.jpg, Dorsi and plantar flexion of the foot
Flexion and extension of the hand
Palmarflexion and dorsiflexion refer to movement of the flexion (palmarflexion) or extension (dorsiflexion) of the hand at the wrist. These terms refer to flexion between the hand and the body's ''dorsal'' surface, which in anatomical position
The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with r ...
is considered the back of the arm; and flexion between the hand and the body's ''palmar'' surface, which in anatomical position is considered the anterior side of the arm. The direction of terms are opposite to those in the foot because of embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
logical rotation of the limbs in opposite directions.
''Palmarflexion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...
'' is flexion of the wrist towards the palm
Palm most commonly refers to:
* Palm of the hand, the central region of the front of the hand
* Palm plants, of family Arecaceae
**List of Arecaceae genera
* Several other plants known as "palm"
Palm or Palms may also refer to:
Music
* Palm (ba ...
and ventral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
side of forearm
The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in anat ...
.
''Dorsiflexion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...
'' is hyperextension
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...
of the wrist
In human anatomy, the wrist is variously defined as (1) the Carpal bones, carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known ...
joint, towards the dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
* Dorsal c ...
side of forearm.
File:Albrecht Dürer Betende Hände.jpg, '' Praying Hands'' by Albrecht Dürer
Albrecht Dürer (; ; hu, Ajtósi Adalbert; 21 May 1471 – 6 April 1528),Müller, Peter O. (1993) ''Substantiv-Derivation in Den Schriften Albrecht Dürers'', Walter de Gruyter. . sometimes spelled in English as Durer (without an umlaut) or Due ...
, demonstrating ''dorsiflexion'' of the hands.
Pronation and supination
Pronation and supination refer generally to the prone
Prone position () is a body position in which the person lies flat with the chest down and the back up. In anatomical terms of location, the dorsal side is up, and the ventral side is down. The supine position is the 180° contrast.
Etymolog ...
(facing down) or supine
In grammar, a supine is a form of verbal noun used in some languages. The term is most often used for Latin, where it is one of the four principal parts of a verb. The word refers to a position of lying on one's back (as opposed to 'prone', lyi ...
(facing up) positions. In the extremities, they refer to rotation of the forearm or foot so that in the standard anatomical position the palm or sole is facing anteriorly when in supination and posteriorly when in pronation. As an example, when a person is typing on a computer keyboard, their hands are pronated; when washing their face, they are supinated.
'' Pronation'' at the forearm
The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in anat ...
is a rotational movement where the hand and upper arm are turned so the thumbs point towards the body. When the forearm and hand are supinated, the thumbs point away from the body. Pronation of the foot is turning of the sole outwards, so that weight is borne on the medial part of the foot.
'' Supination'' of the forearm occurs when the forearm or palm are rotated outwards. Supination of the foot is turning of the sole of the foot inwards, shifting weight to the lateral edge.
File:Braus 1921 306.png, Supination and pronation of the foot
File:Pronation and supination.jpg, Supination and pronation of the arm
Inversion and eversion
Inversion and eversion refer to movements that tilt the sole of the foot away from (eversion) or towards (inversion) the midline of the body.
'' Eversion'' is the movement of the sole of the foot
The sole is the bottom of the foot.
In humans the sole of the foot is anatomically referred to as the plantar aspect.
Structure
The glabrous skin on the sole of the foot lacks the hair and pigmentation found elsewhere on the body, and it has ...
away from the median plane
The median plane also called a mid-sagittal plane is used to describe the sagittal plane as it bisects the body vertically through the midline marked by the navel, dividing the body exactly in left and right side.
The term parasagittal plane is u ...
.
''Inversion
Inversion or inversions may refer to:
Arts
* , a French gay magazine (1924/1925)
* ''Inversion'' (artwork), a 2005 temporary sculpture in Houston, Texas
* Inversion (music), a term with various meanings in music theory and musical set theory
* ...
'' is the movement of the sole towards the median plane
The median plane also called a mid-sagittal plane is used to describe the sagittal plane as it bisects the body vertically through the midline marked by the navel, dividing the body exactly in left and right side.
The term parasagittal plane is u ...
. For example, inversion describes the motion when an ankle is twisted.
File:Eversion_and_inversion.jpg, Example showing inversion and eversion of the foot
Éversion du pied.jpg, Eversion of the right foot
File:Inversion du pied.jpg, Inversion of the right foot
Eyes
Unique terminology is also used to describe the eye. For example:
* A ''version
Version may refer to:
Computing
* Software version, a set of numbers that identify a unique evolution of a computer program
* VERSION (CONFIG.SYS directive), a configuration directive in FreeDOS
Music
* Cover version
* Dub version
* Remix
* ''Ve ...
'' is an eye movement involving both eyes moving synchronously and symmetrically in the same direction.
* ''Torsion
Torsion may refer to:
Science
* Torsion (mechanics), the twisting of an object due to an applied torque
* Torsion of spacetime, the field used in Einstein–Cartan theory and
** Alternatives to general relativity
* Torsion angle, in chemistry
Bi ...
'' is eye movement that affects the vertical axis of the eye, such as the movement made when looking in to the nose.
Jaw and teeth
*''Occlusion
Occlusion may refer to:
Health and fitness
* Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed
* Occlusion miliaria, a skin condition
* Occlusive dressing, an air- and water-tight trauma ...
'' is motion of the mandibula
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
towards the maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
making contact between the teeth.
* ''Protrusion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...
'' and '' retrusion'' are sometimes used to describe the anterior (protrusion) and posterior (retrusion) movement of the jaw.
File:Protrusion_and_retrusion.jpg, Examples showing protrusion and retrusion.
File:Elevation_and_Depression.jpg, Elevation and depression of the jaw.
Other
Other terms include:
* ''Nutation
Nutation () is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behaviour of a mechanism. In an appropriate reference frame ...
'' and ''counternutation'') refer to movement of the sacrum
The sacrum (plural: ''sacra'' or ''sacrums''), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30.
The sacrum situates at the upper, back part ...
defined by the rotation of the promontory
A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the so ...
downwards and anteriorly, as with lumbar extension (nutation); or upwards and posteriorly, as with lumbar flexion (counternutation).
*''Opposition
Opposition may refer to:
Arts and media
* ''Opposition'' (Altars EP), 2011 EP by Christian metalcore band Altars
* The Opposition (band), a London post-punk band
* '' The Opposition with Jordan Klepper'', a late-night television series on Com ...
'' is the movement that involves grasping of the thumb and fingers.
*''Protraction
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relativ ...
'' and '' Retraction'' refer to an anterior (protraction) or posterior (retraction) movement, such as of the arm at the shoulders, although these terms have been criticised as non-specific.
*'' Reciprocal motion'' is alternating motions in opposing directions.
*''Reposition'' is restoring an object to its natural condition.
File:Braus 1921 231.png, Nutation at left, counternutation at right
File:Ok sign.jpg, An example of ''opposition''
File:Opposition_CMX.jpg, Example of ''opposition'' of the thumb and index finger
See also
* Anatomical terms of location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
* Anatomical terms of muscle
* Anatomical terms of bone
Many anatomical terms descriptive of bone are defined in anatomical terminology, and are often derived from Greek and Latin. Bone in the human body is categorized into long bone, short bone, flat bone, irregular bone and sesamoid bone.
Types of ...
* Anatomical terms of neuroanatomy
This article describes anatomical terminology that is used to describe the central and peripheral nervous systems - including the brain, brainstem, spinal cord, and nerves.
Anatomical terminology in neuroanatomy
Neuroanatomy, like other as ...
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External links
Hypermuscle: Muscles in Action at med.umich.edu
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